The first sector on a disk drive used on a personal computer/advanced technology (PC/AT) compatible machine is referred to as MBR. The MBR stores a bootstrap loader, a partition table, and a boot signature.
A basic Input Output System (hereinafter, referred to as BIOS) in the PC/AT compatible machine searches a basic region in which a boot flag is set from the partition table and loads the boot loader recorded in the basic region to a memory using the bootstrap loader in order to boot the personal computer (PC). If the MBR is corrupted, the computer cannot boot.
There are more than a few systems that operate 24 hours×365 days among PC based point-of-sale systems (hereinafter, referred to as POS system). Some commercially available hard disks are sold and used without expecting such long continuous operations. Thus, even a hard disk manufacturer is sometimes not able to identify the cause of a trouble.
Corruption of the partition table in the MBR can cause not only the failure of boot of the PC but also the loss of entire data. As for the troubles due to corruption of the MBR on a silicon disk, the causes of the troubles are not necessarily clarified because the market is currently in the growth stage and the know-how is not sufficiently accumulated.
As the techniques relating to the present invention, Patent Literature 1 describes an invention about a method for determining abnormality in backup data and a method for handling an abnormality in an abnormal case. The data for control and the data for check are verified to determine which data is abnormal in order to restore the data with abnormality. Patent Literature 2 describes an invention about a protected, hidden, emergency boot directory. A backup operating system (OS) of a primary OS is created to load the backup OS in the event of a failure of the primary OS to boot or run. Further, Patent Literature 3 describes an invention about a method for restoring a computer OS. An OS boot program file is checked every time the computer boots in order to restore the corrupted part. Then, the system also checks the hard disk boot information and the like in order to restore the corrupted part. Patent Literature 3 also describes that the information in the boot sector is backed up during the initial backup.